Atherectomy system with guidewire detection

ABSTRACT

An atherectomy system includes a drive mechanism adapted to rotatably actuate an atherectomy burr and a controller that is adapted to regulate operation of the drive mechanism. A guidewire motion detector is adapted to detect movement of the guidewire. The controller is further adapted to take action when the guidewire motion detector detects movement of the guidewire relative to the drive mechanism while the drive mechanism is operating.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. application Ser. No.16/444,761, filed Jun. 18, 2019, the entire disclosure of which ishereby incorporated by reference.

TECHNICAL FIELD

The present disclosure pertains to medical devices, and methods formanufacturing and using medical devices. More particularly, thedisclosure is directed to devices and methods for removing occlusivematerial from a body lumen. Further, the disclosure is directed to anatherectomy device for forming a passageway through an occlusion of abody lumen, such as a blood vessel.

BACKGROUND

Many patients suffer from occluded arteries and other blood vesselswhich restrict blood flow. Occlusions can be partial occlusions thatreduce blood flow through the occluded portion of a blood vessel ortotal occlusions (e.g., chronic total occlusions) that substantiallyblock blood flow through the occluded blood vessel. In some cases astent may be placed in the area of a treated occlusion. However,restenosis may occur in the stent, further occluding the vessel andrestricting blood flow. Revascularization techniques include using avariety of devices to pass through the occlusion to create or enlarge anopening through the occlusion. Atherectomy is one technique in which acatheter having a cutting element thereon is advanced through theocclusion to form or enlarge a pathway through the occlusion. A needremains for alternative atherectomy devices to facilitate crossing anocclusion.

SUMMARY

This disclosure provides design, material, manufacturing method, and usealternatives for medical devices. For example, an atherectomy systemincludes an atherectomy burr and a drive mechanism that is adapted torotatably actuate the atherectomy burr as well as to accommodate aguidewire extending therethrough. A guidewire extends through the drivemechanism. A guidewire motion detector is adapted to detect movement ofthe guidewire. A controller is operably coupled to the guidewire motiondetector and is adapted to regulate operation of the drive mechanism.The controller is further adapted to take action when the guidewiremotion detector detects movement of the guidewire relative to the drivemechanism while the drive mechanism is operating.

Alternatively or additionally, the controller may be further adapted tocease operation of the drive mechanism when the guidewire motiondetector detects movement of the guidewire.

Alternatively or additionally, the controller may be further adapted toprovide an alarm when the guidewire motion detector detects movement ofthe guidewire.

Alternatively or additionally, the guidewire motion detector may befurther adapted to determine whether the guidewire is present within thedrive mechanism.

Alternatively or additionally, the guidewire motion detector may includean optical detector adapted to permit the guidewire to pass through theoptical detector, wherein the presence of the guidewire is detected bythe guidewire blocking at least some of the light passing through theoptical detector.

Alternatively or additionally, the guidewire motion detector may includean axial encoding wheel positioned in contact with the guidewire suchthat translation of the guidewire causes the axial encoding wheel torotate.

Alternatively or additionally, the guidewire motion detector may furtherinclude a position sensing encoder that is positioned to detect rotationof the axial encoding wheel and send an axial motion signal to thecontroller.

Alternatively or additionally, the axial encoding wheel may include aplurality of slots extending through the axial encoding wheel and theguidewire motion detector further comprises an optical sensor sensitiveto changes in light passing through the plurality of slots extendingthrough the axial encoding wheel.

Alternatively or additionally, the guidewire motion detector may includea radial encoding wheel positioned in contact with the guidewire suchthat rotation of the guidewire causes the radial encoding wheel torotate.

Alternatively or additionally, the guidewire motion detector may furtherinclude a position sensing encoder that is positioned to detect rotationof the radial encoding wheel and send a radial motion signal to thecontroller.

Alternatively or additionally, the radial encoding wheel may include aplurality of slots extending through the radial encoding wheel and theguidewire motion detector further comprises an optical sensor sensitiveto changes in light passing through the plurality of slots extendingthrough the radial encoding wheel.

Alternatively or additionally, the guidewire motion detector may includea track ball positioned to contact the guidewire such that translationor rotation of the guidewire causes the track ball to move, a lightsource positioned such that light from the light source impinges on thetrack ball and a light detector positioned such that light reflectedfrom the track ball contacts the light detector, wherein changes in thelight detected by the light detector indicates movement of the trackball and thus indicates movement of the guidewire.

Alternatively or additionally, the guidewire motion detector may includea light source positioned such that light from the light source impingeson the guidewire and a light detector positioned such that lightreflected from the guidewire contacts the light detector, whereinchanges in the light detected by the light detector indicates movementof the guidewire.

Alternatively or additionally, the atherectomy system may furtherinclude a wire brake that facilitates insertion of the guidewire intothe drive mechanism, the guidewire motion detector secured relative tothe wire brake.

Alternatively or additionally, the drive mechanism may include a drivecable coupled with the atherectomy burr and a drive motor adapted torotate the drive cable.

As another example, an atherectomy system includes an atherectomy burrand a drive mechanism that is adapted to rotatably actuate theatherectomy burr as well as to accommodate a guidewire extendingtherethrough. A guidewire extends through the drive mechanism. A firstencoding wheel is positioned in contact with the guidewire such thattranslation of the guidewire relative to the drive mechanism causes thefirst encoding wheel to rotate. A first position sensor is adapted todetect rotation of the first encoding wheel and to output a translationmovement signal. A second encoding wheel is positioned in contact withthe guidewire such that rotation of the guidewire relative to the drivemechanism causes the second encoding wheel to rotate. A second positionsensor is adapted to detect rotation of the second encoding wheel and tooutput a rotation movement signal. A controller is operably coupled tothe guidewire motion detector and is adapted to regulate operation ofthe drive mechanism, and is further adapted to receive the translationmovement signal and/or the rotation movement signal and to take actionwhen either the translation movement signal or the rotation movementsignal indicates guidewire movement relative to the drive mechanism.

Alternatively or additionally, taking action may include at least one ofceasing operating of the drive mechanism and providing an alarm.

Alternatively or additionally, the drive mechanism may include a drivecable coupled with the atherectomy burr and a drive cable that isadapted to rotate the drive cable.

In another example, an atherectomy system includes an atherectomy burrand a drive mechanism that is adapted to rotatably actuate theatherectomy burr as well as to accommodate a guidewire extendingtherethrough. A guidewire extends through the drive mechanism. A trackball is positioned to contact the guidewire such that translation orrotation of the guidewire causes the track ball to move. A light sourceis positioned such that light from the light source impinges on thetrack ball and a light detector is positioned such that light reflectedfrom the track ball contacts the light detector, and changes in thelight detected by the light detector causes the light detector to outputa signal. A controller is operably coupled to the guidewire motiondetector and is adapted to regulate operation of the drive mechanism,and is further adapted to receive the signal from the light detector andto take action when the signal from the light detector indicatesmovement of the guidewire relative to the drive mechanism while thedrive mechanism is operating.

Alternatively or additionally, the drive mechanism may include a drivecable coupled with the atherectomy burr and a drive cable that isadapted to rotate the drive cable.

The above summary of some embodiments is not intended to describe eachdisclosed embodiment or every implementation of the present disclosure.The Figures, and Detailed Description, which follow, more particularlyexemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1 is a schematic block diagram of an example atherectomy system;

FIG. 2 is a schematic block diagram of an example atherectomy system;

FIG. 3 is a schematic block diagram of an example atherectomy system;

FIG. 4 is a schematic block diagram of an example atherectomy system;

FIG. 5 is a schematic block diagram of an example atherectomy system;

FIG. 6 is a schematic block diagram of an example atherectomy system;

FIG. 7 is a schematic view of a guidewire motion detector usable in theexample atherectomy system of FIG. 6 ;

FIG. 8 is a schematic view of a guidewire motion detector usable in theexample atherectomy system of FIG. 6 ;

FIG. 9 is a schematic view of a guidewire motion detector usable in theexample atherectomy system of FIG. 6 ;

FIG. 10 is a schematic view of a guidewire motion detector usable in theexample atherectomy system of FIG. 6 ;

FIG. 11 is a schematic view of a guidewire motion detector usable in theexample atherectomy system of FIG. 6 ; and

FIG. 12 is a perspective view of a guidewire motion detection assemblyusable in the example atherectomy system of FIG. 6 .

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the disclosureto the particular embodiments described. On the contrary, the intentionis to cover all modifications, equivalents, and alternatives fallingwithin the spirit and scope of the disclosure.

DETAILED DESCRIPTION

For the following defined terms, these definitions shall be applied,unless a different definition is given in the claims or elsewhere inthis specification.

All numeric values are herein assumed to be modified by the term“about,” whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In many instances, the terms “about” may include numbers thatare rounded to the nearest significant figure.

The recitation of numerical ranges by endpoints includes all numberswithin that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and5).

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise. As used in this specification and theappended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise.

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of theinvention.

Many patients suffer from occluded arteries, other blood vessels, and/oroccluded ducts or other body lumens which may restrict bodily fluid(e.g. blood, bile, etc.) flow. Occlusions can be partial occlusions thatreduce blood flow through the occluded portion of a blood vessel ortotal occlusions (e.g., chronic total occlusions) that substantiallyblock blood flow through the occluded blood vessel. Revascularizationtechniques include using a variety of devices to pass through theocclusion to create or enlarge an opening through the occlusion.Atherectomy is one technique in which a catheter having a cuttingelement thereon is advanced through the occlusion to form or enlarge apathway through the occlusion. Ideally, the cutting element excises theocclusion without damaging the surrounding vessel wall and/or apreviously implanted stent where restenosis has occurred. However, insome instances the cutting element may be manipulated and/or advancedsuch that it contacts the vessel wall and/or the stent. Therefore, itmay be desirable to utilize materials and/or design an atherectomydevice that can excise an occlusion without damaging the surroundingvessel and/or a previously implanted stent where restenosis hasoccurred. Additionally, it may be desirable that a cutting element beuseful in removing hard occlusive material, such as calcified material,as well as softer occlusive material. The methods and systems disclosedherein may be designed to overcome at least some of the limitations ofprevious atherectomy devices while effectively excising occlusivematerial. For example, some of the devices and methods disclosed hereinmay include cutting elements with unique cutting surface geometriesand/or designs.

FIG. 1 is a schematic block diagram of an example atherectomy system 10that includes a drive mechanism 12 that is adapted to rotatably actuatean atherectomy burr 14. The atherectomy system 10 includes a controller16 that is adapted to regulate operation of the drive mechanism 12. Insome cases, the atherectomy system 10 may include a user interface 18that may be operably coupled to the controller 16 such that thecontroller 16 is able to display information regarding the performanceof the drive mechanism 12. This information may, for example, includeone or more of an instantaneous speed of the drive mechanism 12, aninstantaneous torque being experienced by the atherectomy burr 14, andthe like. In some instances, the atherectomy system 10 may not includethe user interface 18. In some cases, the atherectomy burr 14 may alsobe referred to as being or including a cutting head or a cutting member,and these terms may be used interchangeably.

FIG. 2 is a schematic block diagram of an example atherectomy system 20in which the drive mechanism 12 may include a drive motor 22 and a drivecable 24 that is operably coupled with the drive motor 22 as well as theatherectomy burr 14. In some cases, features of the atherectomy system20 may be combined with features of the atherectomy system 10. In somecases, the atherectomy system 20 may also include a handle (not shown).

FIG. 3 is a schematic block diagram of an example atherectomy system 40that includes a control system 42 that is adapted to regulate operationof the drive mechanism 12 in order to rotatably actuate the atherectomyburr 14. In some cases, features of the atherectomy system 40 may becombined with one or more of the atherectomy system 10 and theatherectomy system 20. The control system 42 may include a referenceblock 32 as well as a Proportional Integral Derivative (PID) controller44 that is operably coupled to the reference block 32. In some cases,the reference block 32 may determine a speed reference 46 that isselectable between a nominal value, a negative value and zero. In someinstances, the PID controller 44 may be further adapted to add an offsetvalue to the speed reference 46 received from the reference block 32,although in some cases, the reference block 32 may add the offset value.The PID controller 44 may be further adapted to provide a reduction inmotor speed of the drive mechanism 12 that is greater than what wouldotherwise normally occur in response to an increasing torque experiencedat the atherectomy burr 14.

FIG. 4 is a schematic block diagram of an example atherectomy system 50that includes a control system 52 that is adapted to regulate operationof the drive motor 22 in order to rotatably actuate the atherectomy burr14. In some cases, features of the atherectomy system 50 may be combinedwith one or more of the atherectomy system 10, the atherectomy system 20or the atherectomy system 40. The control system 52 is operably coupledto the drive motor 22 and includes a feedback loop 54 that is adapted tomonitor performance of the drive motor 22 and to output a control effortsignal 56. A drive circuit 58 is adapted to receive the control effortsignal 56 and to regulate operation of the drive motor 22 in accordancewith the control effort signal 56.

In some cases, the feedback loop 54 may include a reference block fordetermining a speed reference and a Proportional Integral Derivative(PID) controller that is operably coupled to the reference block forreceiving the speed reference, the PID controller adapted to utilize thespeed reference, a Proportional (P) gain value, an Integral (I) gainvalue and a Derivative (D) gain value in determining the control effortsignal. In some cases, the feedback loop 54 may be adapted to add anoffset value to a reference signal provided to the reference loop 54 inorder to accurately hold speed of the drive motor 22 during a no-loadsituation. In some instances, for example if the atherectomy burr 14becomes stuck, the control system 52 may be further adapted to increasethe torque provided by the drive motor 22 until a torque threshold isreached for a brief period of time, and to subsequently direct the drivemotor 22 to reverse at a slow speed in order to unwind energy in thedrive mechanism.

FIG. 5 is a schematic block diagram of an example atherectomy system300. In some cases, the atherectomy system 300 may be considered asbeing an example of the atherectomy system 10, 20, 40 or 50. In someinstances, features of the atherectomy system 300 may be combined withfeatures of any of the atherectomy systems 10, 20, 40 or 50, forexample. The atherectomy system 300 includes a motor 302 that drives adrive cable 304 which itself engages a load 306. The load 306 representsan atherectomy burr, for example. The motor 302 is controlled by a drivecircuitry 308 which may be considered as being an example of orotherwise incorporated into the drive motor 22 (FIG. 2 ) and/or thecontroller 16 (FIGS. 1-2 ), for example. In some cases, the motor 302may be sized, relative to the weight and other dimensions of theatherectomy system 300, to be capable of accelerating the atherectomyburr to full speed in less than 3 seconds, or in some cases in less than2 seconds. As an example, the motor 302 may be rated for at least 60watts. In a particular example, the motor 302 may be rated for about 80watts. These are just examples.

The drive circuitry 308 receives an input from a feedback portion 310.In some cases, the feedback portion 310 begins with a reference input312 from a reference schedule block 314, which provides the referenceinput 312 to a PID controller 316. In some cases, the reference scheduleblock 314 may be configured to accept additional inputs, such as from auser and/or from additional sensors not illustrated. As an example, ifthe device has been running for too long of a period of time, thereference schedule block 314 may reduce the speed reference in order toprevent overheating. A PID controller is a controller that includes a(P) proportional portion, an (I) integral portion and a (D) derivativeportion. The PID controller 316 outputs a control effort value orreference current 318 to the drive circuitry 308. A motor stateestimation block 320 receives a current/voltage signal 322 and a motorposition signal 323 from the drive circuitry 308 and receives statefeedback 324 from the PID controller 316. The motor state estimationblock 320 provides a state feedback signal 325 back to the PIDcontroller 316.

The motor state estimation block 320 outputs a speed value 326 back tothe reference schedule block 314. While the feedback from the motorstate estimation block 320 to the reference schedule block 314 is shownas being a speed value, in some cases the feedback may additionally oralternatively include one or more of position, torque, voltage orcurrent, and in some cases may include the derivative or integral of anyof these values. In some cases, the motor state estimation block 320 mayinstead receive a signal 323 that represents speed, instead of position(as illustrated). The motor position signal 323 may be an indication ofrelative rotational position of an output shaft of the motor 302, andthus an indication of relative rotational position of the load 306,which if tracked over time may provide an indication of speed.

In some cases, the drive circuitry 308 and the feedback loop 310 may incombination be considered as forming a controller 350 that is adapted todetermine an estimated torque at the atherectomy burr (the load 306 asshown in FIG. 5 ). The controller 350 may be considered as being anexample of the controller 16 (FIG. 1 ). In some cases, the controller350 may be considered as including only some elements of the drivecircuitry 308 and the feedback loop 310. In some instances, some of thefeatures and functions of the controller 350 may take place in the motorstate estimation block 320. It will be appreciated that while FIG. 5shows various components as standalone components, in some cases thefunctions of one or more of the components may actually be spreadbetween separate components. In some instances, the functions of one ormore of the components may be combined into one or more components.

If the estimated torque at the load 306 becomes too high, this may be anindication that the burr is getting stuck. In order to protect againstpossible damage to the drive cable 304, and to protect against possibleinjury to the patient, the atherectomy system 300 may be adapted to stopor even reverse operation of the atherectomy system 300 if the estimatedtorque meets or exceeds a predetermined torque threshold. It will beappreciated that the actual value of the predetermined torque thresholdmay vary, depending on the mechanics of the atherectomy system 300, butmay be set at a level low enough to prevent damage and injury, but notset so low as to engender too many false alarms caused by minor and/ortemporary torque increases that are not caused by the load 306 becomingstuck. For example, the instantaneous torque may vary by small amountsas the atherectomy system 300 progresses through the patient'svasculature.

FIG. 6 is a schematic block diagram of an example atherectomy system400. In some cases, the atherectomy system 400 may be considered asbeing an example of the atherectomy system 10, 20, 40 or 50. In someinstances, features of the atherectomy system 400 may be combined withfeatures of any of the atherectomy systems 10, 20, 40 or 50, forexample. The atherectomy system 400 includes a drive mechanism 402 thatis adapted to rotatably actuate the atherectomy burr 306. In someinstances, as shown, the drive mechanism 402 may be considered asincluding the drive motor 302 and the drive cable 304. While shownschematically, it will be appreciated that the drive mechanism 402 maybe adapted to accommodate a guidewire 404 that extends through the drivemechanism 402 and through the atherectomy burr 306.

A guidewire motion detector 406 may be adapted to detect movement of theguidewire 404 relative to the drive mechanism 402. A controller 410,which may be considered as being an example of the controller 16 or thecontroller 350, is operably coupled to the guidewire motion detector 406and is adapted to regulate operation of the drive mechanism 402. Thecontroller 410 is adapted to take action when the guidewire motiondetector 406 detects movement of the guidewire 404 relative to the drivemechanism 402. In some cases, taking action includes stopping operationof the drive mechanism 402. Taking action may additionally oralternatively include the controller 410 providing an alarm such as anauditory alarm, a visual alarm or a vibratory alarm so that the userunderstands that there may be a problem with securement of the guidewire404.

In some cases, the guidewire motion detector 406 may be further adaptedto determine whether the guidewire 404 is present within the drivemechanism 402. For example, the atherectomy system 400 may include(either as part of the guidewire motion detector 406 or as a separatecomponent) a guidewire presence detector 412. The guidewire presencedetector 412 may take any form. The guidewire presence detector 412 may,for example, be an optical device such as may otherwise be used todetect bubbles in a fluid. It will be appreciated that absent theguidewire 404, a certain amount of light will pass through a lumenadapted to accommodate the guidewire 404. With the guidewire 404present, less light will pass through the aforementioned lumen.Accordingly, a light sensor may be used to detect the relative lightlevel, and thus determine whether the guidewire 404 is present. Thisinformation may be communicated to the controller 410. When theguidewire 404 is not present, the controller 410 may alert the user,and/or may not permit operation of the drive mechanism 402.

FIG. 7 is a schematic view of a portion of a guidewire motion detector420 that may be used as the guidewire motion detector 406 (FIG. 6 ). Theguidewire motion detector 420 includes an axial encoding wheel 422 thatis positioned in contact with the guidewire 404 and relative to theguidewire 404 such that translation, or axial movement, of the guidewire404 will cause the axial encoding wheel to rotate about an axis L1.Similarly, the guidewire motion detector 420 includes a radial encodingwheel 424 that is positioned in contact with the guidewire 404 andrelative to the guidewire 404 such that rotation of the guidewire 404will cause the radial encoding wheel 424 to rotate about an axis L2. Itwill be appreciated that the axial encoding wheel 422 and the radialencoding wheel 424 are arranged such that the axis L1 is orthogonal tothe axis L2. The axial encoding wheel 422 may be positioned above orbelow the guidewire 404, for example. The radial encoding wheel 424 maybe positioned above, below, in front of or behind the guidewire 404.

It will be appreciated that motion of either the axial encoding wheel422 or the radial encoding wheel 424, or both, needs to be communicatedto the controller 410. FIG. 8 is a schematic view of a guidewire motiondetector 430. The guidewire motion detector 430 includes an encodingwheel 432 that may, for example, represent either the axial encodingwheel 422 or the radial encoding wheel 424. A position sensing encoder434 is operably coupled with the encoding wheel 432 such that theposition sensing encoder 434 is able to detect when the encoding wheel432 moves. In response to detecting movement of the encoding wheel 432,the position sensing encoder sends a communication informing thecontroller 410. The position sensing encoder 434 may take any form. Theposition sensing encoder 434 may be a mechanical encoder, for example.

In some cases, light may be used to detect movement of the encodingwheel 432. FIG. 9 is a schematic view of a guidewire motion detector 440that includes the encoding wheel 432. As illustrated, the encoding wheel432 includes a number of slots or apertures 442. Light may be emittedfrom a light source 444 and may impinge on the encoding wheel 432. Thelight source 444 may be an LED, a laser or a small incandescent bulb,for example. If the encoding wheel 432 is stationary, any light passingthrough the number of slots or apertures 442 will remain constant.However, if the encoding wheel 432 is rotating, the light passingthrough the number of slots or apertures 442 will change as the lighteither passes through a slot 442 or is blocked by the encoding wheel432. A light detector 446 may be positioned to receive the light passingthrough the encoding wheel 432. The light detector 446 may, for example,be a photodiode, a phototransistor or a photocell. In response todetecting movement of the encoding wheel 432, the light detector 446sends a communication informing the controller 410.

FIG. 10 is a schematic view of a guidewire motion detector 450 thatincludes a track ball 452 that is positioned to contact the guidewire404 such that any translation of the guidewire 404 or any rotation ofthe guidewire 404 causes the track ball to rotate. It will beappreciated that the track ball 452 is free to rotate in any direction.A light source 470 provides a light beam that impinges on the track ball452. In some instances, as illustrated, the light beam may pass throughan optical element 454 that is positioned between the light source 470and the track ball 452. In some instances, the light source 470 may be alaser or a light emitting diode (LED). The optical element 454 may, forexample, be a fiber optic element that enables flexibility in where thelight source 470 may be located. As another example, the optical element454 may be a focusing lens. In some cases, the track ball 452 may be arubber ball, and may have a surface roughness sufficient that movementof the track ball 452 causes changes in how light is reflected by thetrack ball 452. The light reflected by the track ball 452 may passthrough a lens 456 before impinging on a light detector 472. In somecases, the light detector 472 may be positioned to receive light fromthe light source 470 that is reflected by the surface of the track ball452 and that passes through the lens 456. The light detector 472 may bean image processing chip that receives an image formed by the reflectedlight. In response to detecting movement of the track ball 452, thelight detector 472 sends a communication informing the controller 410.

FIG. 11 is a schematic view of a guidewire motion detector 460 that isconfigured to detect movement of the guidewire 404. The light source 454provides a light beam that impinges on the guidewire 404. While notillustrated, in some cases the guidewire 404 may include a polymericcoating that provides the guidewire 404 with a roughness that isappropriate for the guidewire motion detector 460 to function, as insome cases, it is contemplated that the guidewire 404 may have a surfacethat is too smooth to function well with respect to detecting movementvia changes in reflected light. Movement of the guidewire 404 may causechanges in how light is reflected by the guidewire 404. The lightdetector 472 may be positioned to receive light from the light source470 that passes through the optical element 454 before being reflectedby the surface of the guidewire 404 and then passes through the lens456. As before, the optical element 454 may be a fiber optic cable, orthe optical element 454 may be a focusing lens. In some instances, thelight source 470 may be a laser or a light emitting diode (LED). In somecases, the light detector 472 may be a photodetector. The light detector472 may be an optical detector. In some cases, fiber optics may be usedto allow the light source 454 and/or the light detector 456 to be placedaway from the guidewire 404, at a location that is perhaps moredesirable from a packaging standpoint. In response to detecting movementof the guidewire 404, the light detector 472 sends a communicationinforming the controller 410.

FIG. 12 is a perspective view of a guidewire motion detection assembly480. As can be seen, the guidewire motion detection assembly 480includes several components that are secured relative to a circuit board482. The guidewire motion detection assembly 480 includes a wire brake490 that can be actuated between a first position (illustrated) in whichthe guidewire 404 is locked in place and a second position in which theguidewire 404 is free to move relative to the guidewire motion detectionassembly 480. The wire brake 490 includes a clamp lever 492 that isadapted to pivot relative to the circuit board 482 to either lock orunlock the guidewire 404. The wire brake 490 includes a clamp collet 494that selectively engages the guidewire 404.

The lens 456, which is the same lens 456 referenced in FIGS. 10 and 11 ,is secured relative to the circuit board 482. As illustrated, the lens456 is shown as being transparent in order to more easily see the lightdetector 472 secured to the circuit board 482. As shown, the lightdetector 472 is an image processing chip that is operably coupled to thecontroller 410 (FIG. 6 ) such that any detected motion of the guidewire404 may be communicated to the controller 410. A guidewire presencedetector 496 is secured relative to the circuit board 482 and may beconsidered as being an example of the guidewire presence detector 412(FIG. 6 ).

In some cases, the guidewire motion detection assembly 480 may include aguidewire cover 484 that extends between the wire brake 490 and theguidewire presence detector 496. The guidewire cover 484 may beconsidered as providing a lumen for the guidewire 404 to easily extendthrough without running into any other components. In some cases, theguidewire cover 484 may include a slot that exposes the guidewire 404 tolight. With respect to the guidewire motion detector 420 (FIG. 7 ) andthe guidewire motion detector 430 (FIG. 8 ), the lens 456 and the lightdetector 472 shown in FIG. 12 may be omitted. With respect to theguidewire motion detector 450 (FIG. 10 ), it will be appreciated thatthe track ball 452 may be positioned to contact the guidewire 404 andsuch that the light emitted from the light source 470 reflects from thetrack ball 452 and is ultimately reflected to the light detector 472. Insome cases, while not shown, the track ball 452 may be slightlyspring-loaded in order to hold the track ball 452 in sufficient contactwith the guidewire 404 such that movement of the guidewire 404 causesmovement of the track ball 452. With respect to the guidewire motiondetector 460 shown in FIG. 11 , it will be appreciated that the lightsource 470 may be an LED or other light source (not shown) that ismounted to the circuit board 482.

It should be understood that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, and arrangement of steps without exceeding the scope of thedisclosure. This may include, to the extent that it is appropriate, theuse of any of the features of one example embodiment being used in otherembodiments. The invention's scope is, of course, defined in thelanguage in which the appended claims are expressed.

What is claimed is:
 1. A controller for use in an atherectomy system,the atherectomy system including a drive mechanism adapted to rotatablyactuate an atherectomy burr, the drive mechanism adapted to accommodatea guidewire extending therethrough, a guidewire presence detectoradapted to detect whether the guidewire is present, and a guidewiremotion detector adapted to detect movement of the guidewire when theguidewire is present, wherein the controller is adapted to: receivesignals from the guidewire presence detector and the guidewire motiondetector; regulate operation of the drive mechanism; take action whenreceiving a signal from the guidewire motion detector indicating thatthe guidewire motion detector has detected movement of the guidewirerelative to the drive mechanism while the drive mechanism is operating;and prevent operation of the drive mechanism when receiving a signalfrom the guidewire presence detector indicating that the guidewirepresence detector has not detected presence of a guidewire.
 2. Thecontroller of claim 1, wherein the controller is adapted to ceaseoperation of the drive mechanism in response to receiving a signal fromthe guidewire motion detector indicating that the guidewire motiondetector has detected movement of the guidewire.
 3. The controller ofclaim 1, wherein the controller is adapted to output an alarm signal inresponse to receiving a signal from the guidewire motion detectorindicating that the guidewire motion detector has detected movement ofthe guidewire.
 4. The controller of claim 1, wherein the atherectomysystem further includes a wire brake that facilitates insertion of theguidewire into the drive mechanism, the guidewire motion detectorsecured relative to the wire brake.
 5. The controller of claim 1,wherein the drive mechanism comprises: a drive cable coupled with theatherectomy burr; and a drive motor adapted to rotate the drive cable.6. The controller of claim 1, wherein the guidewire motion detectorcomprises an optical detector adapted to: permit the guidewire to passthrough the optical detector; and detect a presence of the guidewire bythe guidewire blocking at least some of the light passing through theoptical detector.
 7. The controller of claim 1, wherein the opticaldetector is adapted to output a signal to the controller indicating thepresence of the guidewire.
 8. The controller of claim 1, wherein theguidewire motion detector comprises: an axial encoding wheel positionedin contact with the guidewire such that translation of the guidewirecauses the axial encoding wheel to rotate; and a position sensingencoder that is positioned to detect rotation of the axial encodingwheel and send an axial motion signal to the controller.
 9. Thecontroller of claim 8, wherein the axial encoding wheel comprises aplurality of slots extending through the axial encoding wheel and theguidewire motion detector further comprises an optical sensor sensitiveto changes in light passing through the plurality of slots extendingthrough the axial encoding wheel.
 10. The controller of claim 1, whereinthe guidewire motion detector comprises: a radial encoding wheelpositioned in contact with the guidewire such that rotation of theguidewire causes the radial encoding wheel to rotate; and a positionsensing encoder that is positioned to detect rotation of the radialencoding wheel and send a radial motion signal to the controller. 11.The controller of claim 10, wherein the radial encoding wheel comprisesa plurality of slots extending through the radial encoding wheel and theguidewire motion detector further comprises an optical sensor sensitiveto changes in light passing through the plurality of slots extendingthrough the radial encoding wheel, the optical sensor adapted to send asignal to the controller.
 12. The controller of claim 1, wherein theguidewire motion detector comprises: a light source positioned such thatlight from the light source impinges on the guidewire; a light detectorpositioned such that light reflected from the guidewire contacts thelight detector; wherein changes in the light detected by the lightdetector indicates movement of the guidewire and cause a signal to beoutputted to the controller.
 13. The atherectomy system of claim 1,further comprising a wire brake that facilitates insertion of theguidewire into the drive mechanism, the guidewire motion detectorsecured relative to the wire brake.
 14. An atherectomy control systemadapted for use with an atherectomy system, the atherectomy systemincluding a drive mechanism adapted to rotatably actuate an atherectomyburr, the drive mechanism adapted to accommodate a guidewire extendingtherethrough, the atherectomy control system comprising: a guidewirepresence detector adapted to detect whether the guidewire is present; aguidewire motion detector adapted to detect movement of the guidewirewhen the guidewire is present; and a controller operably coupled withthe guidewire presence detector and the guidewire motion detector, thecontroller is adapted to: regulate operation of the drive mechanism;take action when the guidewire motion detector indicates that theguidewire motion detector has detected movement of the guidewirerelative to the drive mechanism while the drive mechanism is operating;and prevent operation of the drive mechanism when the guidewire presencedetector indicates that the guidewire presence detector has not detectedpresence of a guidewire.
 15. The atherectomy control system of claim 14,wherein the controller is adapted to cease operation of the drivemechanism in response to the guidewire motion detector indicating thatthe guidewire motion detector has detected movement of the guidewire.16. The atherectomy control system of claim 14, wherein the controlleris adapted to output an alarm signal in response to the guidewire motiondetector indicating that the guidewire motion detector has detectedmovement of the guidewire.
 17. The atherectomy control system of claim14, wherein the guidewire motion detector comprises: a first encodingwheel positioned in contact with the guidewire such that translation ofthe guidewire relative to the drive mechanism causes the first encodingwheel to rotate; a first position sensor adapted to detect rotation ofthe first encoding wheel and to output a translation movement signal tothe controller; a second encoding wheel positioned in contact with theguidewire such that rotation of the guidewire relative to the drivemechanism causes the second encoding wheel to rotate; and a secondposition sensor adapted to detect rotation of the second encoding wheeland to output a rotation movement signal to the controller.
 18. A methodof controlling operation of an atherectomy system, the atherectomysystem including a drive mechanism adapted to rotatably actuate anatherectomy burr, the drive mechanism adapted to accommodate a guidewireextending therethrough, a guidewire presence detector adapted to detectwhether the guidewire is present, and a guidewire motion detectoradapted to detect movement of the guidewire when the guidewire ispresent, the method comprising: receiving signals from the guidewirepresence detector and the guidewire motion detector; regulatingoperation of the drive mechanism in accordance with the signals from theguidewire presence detector and the guidewire motion detector; takingaction when the guidewire motion detector detects movement of theguidewire relative to the drive mechanism while the drive mechanism isoperating; and preventing operation of the drive mechanism when theguidewire presence detector has not detected presence of a guidewire.19. The method of claim 18, wherein taking action comprises ceasingoperation of the drive mechanism when the guidewire motion detectordetects movement of the guidewire.
 20. The method of claim 18, whereintaking action comprises outputting an alarm signal when the guidewiremotion detector detects movement of the guidewire.